These just randomly showed up yesterday under my left breast. They itch like crazy and bled when I scratched them. I don't have anything new. No new detergent or body spray or food or anything. Everything is the same. My little sister has a bunch of itchy bumps too that I touched, but they aren't anywhere besides right under my breast. I have already had chicken pox, my sister hasn't and that's I was looking at hers to see if they are chicken pox, but they were only on her legs, toes, shoulders, and face. Should I be worried? Any idea what they could be? My sister is 8 and I am 20 by the way.